Although the percentage of US women who have had at least one mammogram is rising, there is still a cadre of women who have never been screened, and adherence for routine repeat screening that will decrease mortality is poor. We need to identify mammography interventions that are effective for facilitating routine repeat screening, acceptable to women, and cost-effective for health care providers, managed-care organizations and insurers. In previous research, mammography-promotion interventions delivered via computer programs and telephone counseling have each led to increases in screening but, to date, neither their behavioral outcomes nor their cost effectiveness has been evaluated in direct comparison with each other. This study will compare outcomes from a mammography intervention delivered by computer (CD-ROM) versus telephone. Approximately 1,686 women who are age-eligible for mammography, enrolled in a managed care organization or a large insurance plan, and have not had a mammogram within the previous 15 months will be enrolled in the study. Women will be randomly assigned to receive: (1) a mammography promotion intervention delivered via interactive computer program; (2) the intervention delivered via telephone; or (3) usual care. Computer and telephone interventions will be tailored to recipients' perceptions of susceptibility, benefits and barriers associated with mammography, and perceived self-efficacy for obtaining a mammogram. Women in the computer and telephone groups will receive "booster" interventions 12 months after their first intervention. We will conduct process and outcome evaluations. Outcomes will include mammography adherence and stage of mammography adoption and intervention cost-effectiveness. A logistic regression model will be used to compare the binary outcome of mammography screening adherence by the primary predictor of intervention group, with age, race, and site and their interactions used as covariates. Stage of mammography adoption will be tested using logistic regression with ordinal outcome. Traditional cost and marginal cost-effectiveness analyses are planned.